Improved tap for and mode of cutting dies



W. NEWSHAM. TAP FOR AND MODE OF GUTTING DIBS.L Noz 104,984. Patented July 5, 1870.

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WILLIAMv NEWSHAM, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T0 MORRIS, TASKER & C0., OF SAME PLAOE. I

Letters Patent No. 104,98 4, datcd July 5,1870.

MROVD TA? .FOR AND MODE O1' CUTTING'IDIS.

l'ho Schedule :otoz-red to in those Letter! Patent and making part of the umo.

wO-'hv- I, WILLIAM Nnwsnsm, of the city of Philadelphia, and State of Pennsylvania, have invented an Improved Mode of .Cutting Dies Eccentrically, of which the following'is a specificat'ion.

The nature of my invention consists in a novel mode .of 'giving eccentricity to the .cutting-edges of dies, for

forming. screw-threads on` holts, tubes, Sto., so as to give relief to the same.

The device consists of a tap, which is providedavith `the tap, being only a convenience for holding the cutmovable cntters, which are caused to advance toward its center, and recede therefrom as the tap is rotated,

by suitable mechanism.

The vihratory movement of said cutters is given by avariahle surface of a shaft, cent-rally arranged within the tap, and 'around which the -latter revolves, as here' inafter described.

To enable others skilled in the art to which my improvement appertains to make and use my invention, I will give a detailed description thereof.

In the accompanying drawing, which ,makes a part of i this specification- Figure 1 is a face view of a die to be cut.

Fignre 2 ia sectional view of the die after it is cut, through the line a: z of fig. 1.

Figu-re 3 is a side view of the improved tap B.

Figure 4 is a cross-section, at the -line y y, of fig. 3.

Figure 5 is a side view of the shaft E.

Figure 6 is an end view`of the same.

Fignre 7 is a side view of one of the movahle 'cutters D.

Figure 8 is an end view of the same.

Like letters in all the figures indicate the same parts.

A, figs. 1 and 2, is the die, which has recesses, 'a a a a, between the .cutters b b b b.

The cntting-edges' of the threads, at the points d d d d, are struck from a common centre, e, as represented by the concentric line f.

The eccentricity of the cutters is struck from the Centers sr g g .'1-

The die-plate A having been formed readyforcutting its screw-thread, it is` held invposition, by a suitable chuck, to receive the operation of the tap B, represented in figs. 3 and 4, the said top' being arrangediniline with the center of the die, and rotated by'suitable mechanism. I

Thetap is provided with movable cutters, D D, in' the radial slots h h, the cutters having projecti'ons, jj, at its ends, over which the hands k k, ou the'concentric parts l l of the tap, are slipped, to'hold them within the slots, the cutters being removable at pleas^ ure for repairs by slipping the hands outward.

The handsk are .not essential to the operation of .ters in place whe'n not in service, and may be dispensed with, if desired.

The tap has a central hole, m, clearly seen iu fig. 4, which receives one end of the shait E, .for giving the vihiatory movement to the cutters D D.

That part of the shaft in range with the cntrs has fiat faces, n n n n, represented in figs. t and 5, to admit of the latter receding toward the center of the tap, as represcnted in full lines in fig. 4, which shows the rounded and inner edges of the cuttcrs hearing .upon

said fiat faces.

As the tap revolves, and the full faces o o o o come in contact with the inner edges of the outters, the latter receive an outward movement, and come into. the position represented by dotted lines, whereby eccentricity is given to the dies.

I donot confine myself to the flat fnces n on 'the shaft E, as other formations may be given by meansof curves or corrngations, by which a similar effect Would he produced.

I am aware that expanding taps for cut-ting screwthreads in nuts having various sized orificesare not new, and I disclaim such devices; but

What I do claim is-- The'device, consisting, essentially, of threadedbody or tap B, removabl cutters D, and central shaft E, and the method of using the same'to cut the threads of screw-cuttin'g dies, as described and shown.

In testimony that the above is my invention, I

' have hereuuto set my hand and aflixed my seal, this 12th day of May, 1870.

Witnesses: 'WILLIAM NEWSHAM. [1.. 8.]

THOMAS J. BnwLEY, J osnrn 0. MILLER. 

